Method for producing sockets on pipes



Nov. 29, 1960 R. FouRMANolT 2,962,408

METHOD FOR PRODUCING socKETs oN PIPES Filed May 13, 1955 n.EA-

United States atent la IVUZTHOD FOR PRODUClNG SOCKETS ON PIPES Robert Fonrmanoit, Genoa, Italy, assignor to Eternit Societ per Azioni, Genoa, Italy Filed May 13, 1955, Ser. No. 508,263

Claims priority, application Italy June 7, 1954 7 Claims. (Cl. 154-116) This invention relates to methods and apparatus for producing sockets on the ends of pipes, conduits and the like.

It is an object of the invention to provide improved methods and apparatus whereby sockets are integrated with the ends of pipes in a manner which causes a minimum of stress in the resulting product.

It is a further object of the invention to provide for the production of pipes and the like having axially extending sockets integrated therewith in an improved manner.

Briey, to achieve the above and other of its objectives, the invention contemplates, for example, the mounting of first and second concentric tubular elements on the end of a pipe in such a manner that at least the outermost of the tubular elements extends axially beyond the associated pipe. The invention furthermore contemplates that forces be applied to the tubular elements whereby they are formed, at least in part, into an inclined ange connected in annular fashion to said pipe to support the outermost tubular element which constitutes the major part of the socket. In further accordance with the invention, there is contemplated the application of a force to the tubular elements which is in the nature of a resilient or yieldable force so that a minimum of stress is introduced into the resulting product. Furthermore, a deformation of the tubular elements is contemplated in which the material thereof is minimally displaced so as to provide an excellent resulting and minimal strain pattern.

The accompanying drawing shows, only by way of an example a preferred embodiment of the machine designed for use in practicing the method according to the inventin. In the drawing: Fig. 1 shows a vertical schematic section of the machine, in longitudinal axial direction; Fig. 2 schematically shows, in much smaller scale, a transverse partial section taken along the line II-II of Fig. 1; and Figs. 3, 4 and 5 further show in axial sections 'some examples of ends of socket pipes that can be formed by means of the method and the machine according to the invention. Referring to Fig. l in detail, it will be seen that the illustrated machine includes a stud 1 which by means of tie rods 2, is connected to a plate 3 carrying guides 4 (Fig. l) controlling the radial movement of countermold elements 5 (Figs. 1 and 2) designed to form with their internal surface the countermold. The elements 5, which can easily be changed in order to permit the working of pipes with various diameters, present along their longitudinal edges, sharp cutting rims 6 which cut oif the material which exceeds the capacity of the mould containing it, thereby assuring the reciprocal contact of the elements 5 and a perfectly smooth and containuous internal surface in the countermold. The elements 5 are actuated by means of the pistons 8 of cylinders 9 carried by the plate 3. The outside surface of the elements 5 has a frustoconical shape, as at 10, for co-operation with a similarly shaped end portion of the internal surface of a cylinder 11 which is mounted in slidable manner on ange 12, on a rigid body 13 of the machine. The cylinder 11 comprises an annular inside projection 14, provided with gaskets, forming with respect to the body 13 the two chambers 15 and 16 respectively supplied with pressure iiuid through the exible ducts 17 and 18. A moulding head 19, which is placed so as to be capable of being easily changed in order to permit the working of pipes having various diameters and which is designed for cooperation with the countermold 5, is supported by a tube or rod 20 and has a cylindrical outer surface on its largest portion 21, of a diameter which corresponds to the desired internal diameter of the socket, narrowed cylin drical portion 22 the diameter of which is smaller than the internal diameter of a tube or pipe 65, and a shoulder 23 extending between the cylindrical surfaces of elements 2 1 and 22.

The elements 5 of the countermold have correspondingly a cylindrical surface 25 corresponding to the outside diameter of the socket, a narrow, inclined connecting surface or portion 26 extending from the surface 25 and having a minimum diameter equal to the diameter of the outer surface 7 of pipe 65, and a further surface 27 oppositely inclined towards the outside of the countermold. On the inside end of the cylindrical portion 22 of the head 19 and lying against the at radial surface or shoulder 23, a rubber or vdeformable ring 28 is placed, the external surface of which corresponds to the inside surface of the pipe. An annular piston 29 presses against the free end face of ring 28 with a pressure that can be adjusted by means of a nut 32 engaged by one end of a spring 30 which is, in turn, acted upon by a rod 31 supplied with a nut and a lock-nut assembly 41 operating through a disc 33 against the other end of spring 30. Between the nut 32 andthe bottom of head 19, a return spring 79 is placed. The tube or rod 20 terminates, at its other end, in a piston 34 on which a cylinder 35 is formed, receiving a piston 36 on the end of rod 31. Piston 34 is received in a cylinder 37 formed as a part of the xed body. The two working chambers 38 and 39 formed in the cylinder 35 on opposite sides of piston 36 are respectively communicated, by means ofthe ducts 40 and 41, with the working chambers 42 and 43 on opposite sides of the piston 34 in the cylinder 37. The chambers 42 and 43 are supplied with openings 44 and 45 for the operating uid.

rlhe rod 20, between its two ends, has a radial shoulder or abutment 49 defining the` end of a portion 50 having a smaller diameter. A tubular rod 51V of a .piston is slidable on portion 50, and the piston 52 is received in a cylinder 53 forming part of the xed body. Two working chambers 54 and S5 are formed in the cylinder 53 at the opposite sides of piston 52 and communicate, by means of ducts 56 and 57, with a source of pressure Huid.

The fixed body of the machine further has, between the cylinder 53 and the working head 19, another cylinder 58 in which la piston 59 is received forming two working chambers 60 and 61 which are respectively connected-to a source or pressure fluid by means of ducts 62 and 63; the last one being extended by means of duct 64 to the end of chamber 61 towards the head 19.

Referring to Figs. 1 and 3, it may be seen that a tubular element 66 of asbestos-cement is tted on the end of the pipe 65 which is to be formed with a socket, and a tubular element 69, also of asbestos-cement, is fitted on the tubular element 66 with the end 70 of element 69 being axially displaced with respect to the adjacent ends 71 of the ele ment 66.

The operation of the machine described above is as follows, the blocks 5 being initially moved apart in the direction of the arrows 75, Fig. 2 and the other parts of the machine being in their rest positions, as shown in Fig. 1.

Pressure luid is supplied through duct 44` by means of which the piston 34, the rod 20 and the head 19 are displaced in the direction of the arrow 74 and the head 19 will project toward the right as viewed in Fig. 1 with respect to plate 3. Before the piston 34 contacts the end of cylinder 37, the pressure in working chambers 38 and 42 is interrupted by means (not shown) within the ducts connected to the chambers 38 and 42. In this Way, the working of rod 31 and of the annular piston 29 is eliminated at the beginning and at the end of the cycle; that is, during the step of assembling the elements to be pressed and the step of removing the pressed tube. The assembly shown in Fig. 3 is then fitted on head 19 and on the cylindrical surface of the ring 28. Then pressure fluid is supplied through duct 45, so that the piston 34 will be displaced in the direction of arrow 73 and make the head 19 carrying the assembly of Fig. 3 enter hole 72 of plate 3. The working chambers 77 of cylinders 9 are then supplied with pressure fluid so that the elements 5 are pushed in the directions of the arrows 76, towards the axis of the pipe and of the machine, While the sharp rims 6 will insure that the internal surface of the countermold constituted by the elements 5 is smooth. Then the pressure uid is supplied through duct 17 to chamber 15, so that the sleeve 11 is pushed in the direction of arrow 74 and acts on the outside frustoconical surface of the elements 5 so that a blocking thereof is assured. Next, high pressure fluid is supplied through duct 44 into chamber y42. The piston 34 and the rod 20 are therefore pushed in the direction of arrow 74 to move the end surfaces 70 and 71 of the tubular elements 69 and 66 on the end of pipe 65 into contact with the inclined surface 26 of the countermold. During such movement the pressure in chambers 42 and 38 is limited, because it is restricted only by the frictional resistance to displacement of the rod 20. At the time of contact, the pressure in chambers 42 and 38 is brought to its preestablished value, so that, at the time the material to be compressed is put under pressure between surface 26 and radial surface 23, rod 31 is operating in the direction of the arrow 73 with respect to rod 20. Such movement of rod 31 produces a pushing action on the annular piston 29 in the direction of the arrow 73, through the action of the nuts 32, 41 on sp-ring 30 which has been previously compressed and functions to limit the stress. The push of piston 29 is transmitted to the elastic ring 28, causing the latter to bulge and to exert a radially outward force against the end portion of the pipe 65. The slight movement of the head 19 in the direction of arrow 74 simultaneously produces, owing to the inclined surface 26 of the countermold, an inclined surface 81 on the socket (Fig. 3), which surface may be consideredan average of the step edge d, e, f, g (Fig. 3).

According to the above, the deformation of the material is slight to the left of the generatrix of surface 81 (Fig. 3), while substantially all the other parts of the elements co-operating in the construction of the socket remain fully undeformed with extreme advantage for the characteristics of the material Iand of the socket obtained thereby.

Directly after the above-mentioned slight deformation, pressure tluid is supplied through duct 57 so that the iston 52 with its tubular extension 51 will press against the abutment 49 and therefore cause a strong ramming by the head 19 into the countermold, and at the same time or with a slight delay, fluid will be supplied through duct 62 with the result that piston 59 will press the rod 82 and the annular edge 83 against the end edge 84 of the tubular element 69. The operation may also be retimed so that before pressure uid is supplied through duct 62, pressure uid is supplied through duct 57.

It will be seen that the zone immediately near surface 81 (Fig. 3), that is, the zone in which the slight deformation of the asbestos-cement material for forming the 4. socket takes place, is remote from the zone of the formed socket which is stressed following installation of the pipe. Pressing is effected by means of successive pressure actions, which are independent from each other, in time as well as in intensity and is, at least in part, eected in elastic manner through the ring 28.

In order to be able to remove the pipe having a socket thereon from the machine, chamber 61 is put under pressure and the piston 82 is drawn back. Then the chamber 54 is put under pressure and the piston 52 is drawn back; while the rod Ztl is slightly drawn back by feeding of pressure fluid to chamber 43. Simultaneously, there is a pushing back of the rocl 31 and the rubber ring 28 is freed. Finally, by supplying pressure uid to chamber 16, cylinder 11 will be retracted and then the chambers 77 of cylinders 9 are put under pressure such that elements 5 are displaced in the direction of the arrows '75. This done, when pressure fluid is supplied to chamber 42 of cylinder 37, an ample displacement in the direction of arrow 74 of the head 19 and of the pipe with the socket formed thereon is obtained. It is evident that all these operations are automatically executed in proper sequence by means o-f a suitable conventional device the details thereof forming no part of this invention and which therefore are not described.

The pipe thus projected through the plate 3 may be removed frorn the head 19.

It is obvious that, in place of the elements 66, 69 on the pipe 63 in Fig. 3, it is possible to use a single element 85, shaped as it is shown in Fig. 4, or a single element 86, shaped as shown in Fig. 5.

Although an illustrative embodiment of the invention has been described in detail herein with reference to the accompanying drawing, it is to be noted that the invention is not limited to that particular embodiment, and that various changes and modifications may be effected therein without departing from the scope or spirit of the invention, except as defined in the appended claims.

What is claimed is:

1. A method for producing a socket on the end of a pipe of asbestos-cement material comprising the steps of forming a pipe of asbestos-cement material, forming a tubular structure of asbestos-cement material having a shape corresponding generally to the shape o-f the desired socket with an internal diameter at one end portion of the tubular structure only slightly greater than the external diameter of the pipe on which a socket is to be produced, placing said one end portion of the tubular structure over an end of the pipe with the remainder of the tubular structure projecting axially beyond said end of the pipe, and applying axial pressures to said tubular structure and said end of the pipe and a yieldable radially outward pressure to said end of the pipe to unite said tubular structure and said pipe with said remainder of the tubular structure defining a socket at said end of the pipe while excessive deformation is avoided in the asbestos-cement material forming a junction between said socket and said pipe.

2. A method as in claim 1; wherein said remainder of the tubular structure has an internal diameter substantially greater than said internal diameter at said one end portion so that, when said socket is produced on said end of the pipe, another pipe can be inserted in the socket with a gasket accommodated between said socket and said other pipe.

3. A method as in claim 2; wherein said tubular structure consists of a single tubular element of stepped internal configuration to provide different internal diameters at said one end portion and at said remainder, respectively.

4. A method as in claim 2; wherein said tubular structure includes at least two tubular elements of different diameters in partially telescoped relationship to define said one end portion having a relatively small internal diameter and said remainder having a relatively larger internal diameter.

5. A method as in claim 2; wherein said tubular struc ture has relatively larger and smaller external diameters at said remainder and said one end portion, respectively, with external and internal transitional surfaces between said one end portion and said remainder which are spaced apart axially, and wherein said pressures are applied t0 slightly deform the asbestos-cement material of said tubular structure only in the region of said external transitional surface.

6. A method as in claim 5; wherein said pressures are applied in independent steps during which the individual pressures are variable.

7. A method as in claim 5; wherein said pressures are applied by exerting two distinct, opposed axial pressures against said internal and external transitional surfaces.

References Cited in the le of this patent UNITED STATES PATENTS Chapman Dec. 210, 1892 Werner Nov. 1, 1932 Coyle July 15, 1947 Magnani Oct. 3l, 1950 Hjulian Apr. 7, 1951 Hjulian Nov. 16, 1954 Prenveille et al. Jan. 3, 1956 Pickering Ian. 10, 1956 Stout Oct. 30, 1956 Walker et al Feb. 26, 1957 Stephens Feb. 26, 1957 

1. A METHOD FOR PRODUCING A SOCKET ON THE END OF A PIPE OF ASBESTOS-CEMENT MATERIAL COMPRISING THE STEPS OF FORMING A PIPE OF ASBETOS-CEMENT MATERIAL, FORMING A TUBULAR STRUCTURE OF ASBESTOR-CEMENT MATERIAL HAVING A SHAPE CORRESPONDING GENERALLY TO THE SHAPE OF THE DESIRED SOCKET WITH AN INTERNAL DIAMETER AT ONE END PORTION OF THE TUBULAR STRUCTURE ONLY SLIGHTLY GREATER THAN THE EXTERNAL DIAMETER OF THE PIPE ON WHICH A SOCKET IS TO BE PRODUCED, PLACING SAID ONE END PORTION OF THE TUBULAR STRUCTURE OVER AN END OF THE PIPE WITH THE REMAINDER OF THE TUBULAR STRUCTURE PROJECTING AXIALLY BEYOND SAID END OF THE PIPE, AND APPLYING AXIAL PRESSURES TO SAID TUBULAR STRUCTURE AND SAID END OF THE PIPE AND A YIELDABLE RADIALLY OUTWARD PRESSURE TO SAID END OF THE PIPE TO UNITE SAID TUBULAR STRUCTURE AND SAID PIPE WITH SAID REMAINDER OF THE TUBULAR STRUCTURE DEFINING A SOCKET AT SAID END OF THE PIPE WHILE EXCESSIVE DEFORMATION IS AVOIDED IN THE ASBESTOS-CEMENT MATERIAL FORMING A JUNCTION BETWEEN SAID SOCKET AND SAID PIPE. 